A semiconductor device generally includes a circuit board or a lead frame (hereinafter circuit board). A semiconductor die is generally mounted to and electrically connected to the circuit board. The connection between the semiconductor die and the circuit board is performed by a connecting member such as conductive wire to bond pads on the semiconductor die and the circuit board.
The conductive wire is widely used in many kinds of semiconductor devices as it has good workability and provides good signal transmitting performance. The conductive wire used in the semiconductor device is generally fabricated using high-purity metals so as to maintain the moldability and electrical transmitting properties.
However, using high-purity wire materials do have certain drawbacks that may reduce reliability of the semiconductor device using the conductive wire. One of the issues is that the conductive wire forms an intermetallic compound (IMC) with the bond pad. IMCs are chemical compounds formed by two metallic chemical elements. The resulting compounds are chemically different from either of the two constituents. The IMC formed by the conductive wire and the bond pad results in kirkendall voids or cracks between the bond pad and the conductive wire. Kirkendall voids or cracks are formed by bonding different pure metals that have different interdiffusion coefficients. The voids/cracks cause the electric conductivity of the conductive wire to drops. Furthermore, the voids/cracks could cause the conductive wire to break. These problems are main factors reducing the reliability and the production yield of the semiconductor device.
Therefore, a need existed to provide a device and method to overcome the above problems.